Rainfall partitioning through a mixed cedar swamp and associated C and N fluxes in Southern Ontario,Canada     

Tim P. Duval 《水文研究》2019,33(11):1510-1524

Partitioning of rainfall through a forest canopy into throughfall, stemflow, and canopy interception is a critical process in the water cycle, and the contact of precipitation with vegetated surfaces leads to increased delivery of solutes to the forest floor. This study investigates the rainfall partitioning over a growing season through a temperate, riparian, mixed coniferous‐deciduous cedar swamp, an ecosystem not well studied with respect to this process. Seasonal throughfall, stemflow, and interception were 69.2%, 1.5%, and 29.3% of recorded above‐canopy precipitation, respectively. Event throughfall ranged from a low of 31.5 ± 6.8% for a small 0.8‐mm event to a high of 82.9 ± 2.4% for a large 42.7‐mm event. Rain fluxes of at least 8 mm were needed to generate stemflow from all instrumented trees. Most trees had funnelling ratios <1.0, with an exponential decrease in funnelling ratio with increasing tree size. Despite this, stand‐scale funnelling ratios averaged 2.81 ± 1.73, indicating equivalent depth of water delivered across the swamp floor by stemflow was greater than incident precipitation. Throughfall dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) averaged 26.60 ± 2.96 and 2.02 ± 0.16 mg L^?1, respectively, which were ~11 and three times above‐canopy rain levels. Stemflow DOC averaged 73.33 ± 7.43 mg L^?1, 35 times higher than precipitation, and TDN was 4.45 ± 0.56 mg L^?1, 7.5 times higher than rain. Stemflow DOC concentration was highest from Populus balsamifera and TDN greatest from Thuja occidentalis trees. Although total below‐canopy flux of TDN increased with increasing event size, DOC flux was greatest for events 20–30 mm, suggesting a canopy storage threshold of DOC was readily diluted. In addition to documenting rainfall partitioning in a novel ecosystem, this study demonstrates the excess carbon and nitrogen delivered to riparian swamps, suggesting the assimilative capacity of these zones may be underestimated.  相似文献   

太湖藻型湖区沉积物中生物易降解物质组成及分布规律   总被引：2，自引：0，他引：2  

祁闯  方家琪  张利民  雷波  汤响成  王国祥 《湖泊科学》2019,31(4):941-949

为研究富营养化湖泊藻型湖区沉积物中生物易降解有机质的组成及其垂向分布特征，选取太湖竺山湾湖滨带和开敞湖区采集沉积物柱状样，利用微电极技术测定沉积物-水界面理化指标的剖面特征，并对沉积物中含水率、烧失量、色素含量、总有机碳、总氮以及生物易降解物质（总蛋白、总糖和总脂）进行测定.结果表明：藻型湖区沉积物-水界面处溶解氧、pH和氧化还原电位在垂向剖面上呈现出随深度增加而下降的趋势，空间上存在明显的异质性，湖滨带沉积物-水界面溶解氧、pH和氧化还原电位显著低于开敞湖区，而沉积物-水界面H₂S浓度在垂向上则表现为随深度先降低而后升高的趋势.此外，藻型湖区沉积物中生物易降解有机质的组成和分布同样存在明显的空间异质性.组成上以脂类（7.7 mg/g）为主，其次是糖类（4.5 mg/g），蛋白质（0.8 mg/g）含量最低；空间上，湖滨带沉积物中生物易降解有机质含量显著高于开敞湖区，表层15 cm以上沉积物含水率和烧失量较高，有机质含量丰富.  相似文献   

营养限制对三种浮游动物的影响   总被引：1，自引：0，他引：1  

陈蕾  李超伦  周孔霖  时永强  刘梦坛 《海洋学报(英文版)》2018,37(4):58-68

Nutrient imbalance—a mismatch in nutrient ratios between the available food supply and the demands of consumers—has the potential to be transported up food chains,exposing zooplankton to nutrient limitations.In this study,the response of Calanus sinicus(copepod),Moina mongolica(cladocera),and Brachionus plicatilis(rotifer) to nutrient-limited(no-limited,P-limited,and N-limited) food were evaluated from the perspective of growth,reproduction,and stoichiometric homoeostasis.The results indicated that the growth of three species was suppressed under nutrient-limited(especially P-limited) conditions.However,the effect of nutrient limitations on their reproduction was species-specific.For C.sinicus,the dietary UFA(unsaturated fatty acid) as a major phospholipid component affected their egg production and total FA supporting energy promoted the hatchability of eggs.Furthermore,excess carbon in the diet promoted egg production but reduced hatching success.For M.mongolica,nutritional(P and UFA) and energy(total FA) support affected their fecundity.B.plicatilis fecundity exhibited the same pattern of growth(no-limitedN-limitedP-limited).In terms of stoichiometric homeostasis,B.plicatilis' s elemental compositions were less likely to be affected by nutrient limitations than M.mongolica.We suggest that the effects of nutrient imbalances could potentially become an evolutionary force affecting ecosystem structure and stability in eutrophic waters.  相似文献   

海马齿浮床对富营养化海湾营养盐削减的模型评价：以东山湾八尺门养殖海域为例     

刘学海  蒲新明  罗东莲  芦静  刘自力 《海洋学报(英文版)》2019,38(12):91-100

Many coastal seas are severely eutrophic and required to reduce nutrient concentrations to meet a certain water quality standard. We proposed a method for nutrient removal by planting Sesuvium portulacastrum at the water surface using the floating beds in the aquaculture area of the Dongshan Bay as an example, which is an important net-cage culture base in China and where dissolved inorganic nitrogen(DIN) and dissolved inorganic phosphate(DIP) reach 0.75 mg/L and 0.097 mg/L, respectively far exceeding China's Grade IV water quality standards.Numerical simulations were taken using the ecological model, field observations and field plantation experimental results to assess the environmental restoration effects of planting S. portulacastrum at some certain spatial scales. Our field experiments suggested that the herbs can absorb 377 g/m~2 nitrogen and 22.9 g/m~2 phosphorus in eight months with an inserting density of ～60 shoot/m~2. The numerical experiments show that the greater the plantation area is, the more nutrient removal. Plantation in ～12% of the study area could lower nutrients to the required Grade II standards, i.e., 0.2 mg/LDIN≤0.3 mg/L and 0.015 mg/LDIP≤0.03 mg/L.Here the phytoremediation method and results provide helpful references for environmental restoration in other eutrophic seas.  相似文献   

黑龙江海伦地区垦殖前后典型黑土剖面主要养分元素垂直分布特征     

宋运红  张哲寰  杨凤超  梁帅  魏明辉  刘凯  许江 《地质与资源》2021,29(6):543-549

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黑龙江省海伦市长发镇土地质量地球化学评价及开发建议     

刘国栋  杨泽  戴慧敏  张一鹤  肖红叶  陈江 《地质与资源》2021,29(6):533-542

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杭州湾及邻近水域营养盐的时空分布与富营养化特征   总被引：7，自引：0，他引：7  

高生泉  陈建芳  金海燕  王奎  卢勇  李宏亮  陈法锦 《海洋学研究》2011,(3):36-47

利用2006年7月-2007年11月杭州湾及邻近水域春、夏、秋、冬四个季节的调查资料,对其营养盐的分布变化及富营养化特征进行了分析.结果表明:杭州湾及邻近水域营养盐的分布变化和富营养化不仅与湾内河流高DIN、磷、硅的输入直接有关,同时受长江冲淡水的影响十分显著.湾内营养盐的分布变化主要受物理混合作用所控制,浮游生物活动...  相似文献   

日本枪乌贼的营养成分分析   总被引：2，自引：0，他引：2  

刘玉锋  毛阳  王远红  吕志华 《中国海洋大学学报(自然科学版)》2011,(Z1):341-343

本文采用国家标准营养分析方法及仪器分析方法测定了日本枪乌贼的营养成分。结果表明,日本枪乌贼中粗蛋白含量9.29%,粗脂肪含量1.43%,水分含量85.82%,灰分含量1.79%;18种氨基酸占总干重的55.09%,8种必需氨基酸占氨基酸总量的44.46%,必需氨基酸与非必需氨基酸比值0.80;多不饱和脂肪酸二十二碳六烯酸DHA、二十碳五烯酸EPA、二十碳四烯酸ARA及十八碳二烯酸LA之和占总脂肪酸含量的24.94%;富含无机元素镁,磷,钙,锌。日本枪乌贼蛋白质含量较高,必需氨基酸含量较丰富,粗脂肪含量较低,是营养价值较高的一种海产品。  相似文献   

Harmful algal blooms and eutrophication: ��strategies�� for nutrient uptake and growth outside the Redfield comfort zone     

Patricia M. GLIBERT  JoAnn M. BURKHOLDER 《中国海洋湖沼学报》2011,29(4):724-738

While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.  相似文献   

Response of nutrients and the surface phytoplankton community to ice melting in the central Arctic Ocean   总被引：3，自引：0，他引：3  

ZHUANG Yanpei  JIN Haiyan  CHEN Jianfang  WANG Bin  LI Hongliang  CHEN Fajin  LU Yong  XU Jie 《极地研究(英文版)》2011,(4):266-272

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